<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<style>
    .nav1 {
        width: 100%;
        height: 64px;
        background: olivedrab;
    }

    .nav1 {
        width: 100%;
        height: 64px;
        background: rgba(255,1,0,0.5);
        position: absolute;
    }
</style>

</head>
<body>
<div class="nav1">

</div>
<div class="nav">

</div>
</body>
</body>
</html>